Various methods and apparatus are known for fixating a damaged bone joint or a fracture to allow fusion to take place. In a typical procedure, the opposing bone surfaces of the joint or fracture are first made planar by sawing and/or smoothing. Next a bore is drilled through the joint or fracture and a compression screw is then inserted into the bore and a compressive force is applied to the joint or fracture to allow the fusion process to occur.
Especially with the small bones and joints of the finger, the integrity of a fused joint is often largely dependent upon the skill of the surgeon in accurately positioning and aligning the cutting and drilling instruments to make properly angled cuts and bores. Although it is well known for a surgeon to use a template or guide to achieve precise angles in certain cutting and drilling procedures, the techniques and instruments of the prior art are ill-suited for fusion procedures on the small bones of the finger.
The fusion methods of the prior art teach the use of an individual template for positioning a saw blade to make a properly angled cut and a separate drill guide for drilling a guide bore. As two separate instruments are used, each template or guide must be individually aligned and secured before each step, increasing both the time of the surgery and the chance of misalignment. Furthermore, most of the prior art templates and guides are designed for fusion procedures on large joints and bones, such as the femur, and none are specifically designed for use on the much smaller phalanxes of the fingers. Examples of prior art saw guides and separate drill templates are U.S. Pat. No. 5,250,050 to Poggie et al. and U.S. Pat. No. 5,176,685 to Rayhack.
It is also well known to use a fixation plate and a corresponding compression instrument, such as a screw, to stabilize and compress the joint or fracture together to allow it to fuse. The fixation plate is typically affixed directly to the bone to be repaired and the compression screw is inserted through an aperture in the plate and into the guide bore drilled through the damaged joint or fracture. The screw is anchored in the distal end of the joint/fracture and engages the fixation plate to create a compressive force. Examples of typical fixation plates and compression screws are shown in U.S. Pat. No. 4,776,330 to Chapman et al. and U.S. Pat. No. 5,041,116 to Wilson.
However, like the prior art templates and guides, the prior art fixation plates and compression screws are designed to be used on large bones and joints and are ill-suited for use on the smaller bones and joints of the finger. In particular, the fixation plates of the prior art are designed for subcutaneous fixation and include bone screws that are randomly placed along the plate for direct engagement with the bone. These designs are not suited for attachment to the top of a finger, as the bone screws will damage the underlying extensor digitorum tendon.
The compression screws of the prior art are also primarily designed for use on fractures as opposed to damaged joints, in addition to being suitable only for large diameter bones. Many of the prior art designs are comprised of multiple concentric screws and/or sleeve assemblies that must fit into a single bore that is drilled through the fracture. For example, the compression screw assembly taught in the '330 patent to Chapman et al. requires that a separate expansion sleeve, plunger, insertion rod and guide wire all be inserted into the fractured bone. Although well-suited for use on a fractured femur head, the numerous components and wide profile of this design makes the assembly much too cumbersome to be used on the small diameter bones of the finger. Additionally, the numerous components of this design require multiple steps for installation, thereby increasing the overall time and complexity of the fusion procedure.
Thus, as demonstrated by the limitations of the prior art, there is a need identified for a joint fixation system and method that allows the surgeon to accurately and efficiently perform fusion procedures on joints in the fingers. In addition, a related tool kit containing instruments that are specifically designed for fusion procedures on the small bones in the fingers is desired.